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I'm currently working on a scientific work regarding electric fields created by avalanche beacons. My question is what kind of field is created around the antennas of such device? Is it a dipole (2 different Sheres) or does it behave like a spool (=a cylinder made of wires)?

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  • $\begingroup$ 2 different Spheres means for example a positive metal ball and a negative one $\endgroup$ – Simon Trakis Jun 22 '19 at 13:02
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The antennas are magnetic dipoles. The frequency and field strength is defined by the ETSI standard.

457kHz +/- 80 Hz because this low frequency is minimally affected by snow and other avy debris. The intention is that all the beacons are on the same frequency allowing for manufacturing and component tolerances.

https://www.etsi.org/deliver/etsi_en/300700_300799/30071801/02.01.00_20/en_30071801v020100a.pdf

The range of these beacons is very short relative to the wavelength. At these short distances, the normal behavior of a magnetic loop antenna does not apply. https://en.wiktionary.org/wiki/radiansphere

You may find this helpful: https://www.researchgate.net/publication/263412970_Simple_Formulas_for_Near-Field_Transmission_Gain_and_Fields/download

Feel free to contact me directly at david(dot)vanhorn(at)backcountryaccess(dot)com

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